The present invention relates to a holder for holding a plurality of sheets. The invention is particularly useful as a holder for holding computer printout sheets, and is therefore described below with respect to this application.
Computer printout sheets represent a widely used means for presenting all kinds of data. As increasing amounts of such data accumulate, and storage space becomes more expensive, there is an increasing need for filing systems employing holders that are capable of providing efficient paper storage while taking up a minimum of space.
The presently-used filing systems employ a large variety of soft or hard cover holders of the following types:
(1) Holders which do not include sheet-securing mechanisms, such that the plurality of sheets are loosely stored with the result that locating and extracting a given sheet is inefficient and the sheets may become disarranged in order. The main advantage of this system is that such holders need be only as thick as the stack of sheets stored and may thus be space-saving.
(2) Holders which include sheet-securing mechanisms, such that the sheets are perforated and are stacked on posts or arms which are clampable to enable efficient securing. One form of such holder employing bendable posts or arms has the advantage of not adding thickness to the holder, and is thus space-saving during storage. However, this type has the following disadvantages: (i) the posts or arms onto which the sheets are stacked are of a standard diameter and of a standard distance between posts, requiring specific perforation of sheets before stacking; and (ii) once stacked and clamped, the retrieval and extraction and/or insertion of a sheet within the stack requires removal of all sheets above the particular sheet.
(3) Holders (sometimes called the "lever-arch" file-type holder) which employ arch-shaped posts each with two arms separable via a lever, or in some cases manually, to allow insertion/extraction of a specific sheet. The advantage of this holder is that it permits a sheet to be inserted/extracted at a given location without the removal of the overlying sheets. A disadvantage, however, is that the "lever arch" type post has a standard height, not all of which can be utilized to stack sheets, as the "arch" section has to be free of sheets. Thus, this holder has a thickness greater than the stack of sheets to be stored, resulting in a waste of storage space. The arch-type posts also have a set distance between each other requiring specific perforation of the sheets to be stacked. In addition, most of these holders employing sheet-stacking posts do not have their posts spaced to accommodate the pre-formed perforations commonly present in computer printouts.
A number of sheet-holder systems have been described, for example, in U.S. Pat. Nos. 1,004,777, 1,644,541, and 4,775,257, and in British Patent No. 802,577, which employ flexible cords for securing the stack of sheets within the holder. However, none of the devices described can efficiently and compactly hold various numbers of sheets, of different arrangements of perforations, and permit the sheet holding capacity to be increased or decreased as may be required.